Liquid beverages, such as wine, are often sold in bag-in-a-box packaging that includes a flexible bag or liner positioned in a box and connected to a tap or faucet that extends out of the box. The liquid is stored in the bag and a user dispenses the liquid from the packaging by activating the tap. Some liquid beverages, such as wine, that are stored and sold in a bag-in-a-box packaging system are highly oxygen sensitive. That is, exposure to oxygen can cause the wine to spoil and therefore affect the shelf life of the wine. The bags for such packaging systems are typically made from a film of ethylene vinyl alcohol (“EVOH”).
Wine manufacturers add sulfites to packaged wine that act as a preservative to prevent spoilage and oxidation of the wine. While EVOH-based films provide a barrier to oxygen transfer, the EVOH films from which the liner bags are made do not completely prevent oxygen from seeping into the bag over time. That is, oxygen can enter the bag through the film of the bag from the outside environment at a given oxygen transmission rate (“OTR”). Typical wine bag films have an OTR of 0.05 cc/100 in2/day at 73 degrees Fahrenheit and 0% relative humidity. As oxygen enters the bag from the external environment, the oxygen uses up the sulfite preservatives in the bag and can then react or oxidize the wine, which spoils it. Oxygen can also enter the bag through the tap to which the bag is connected. Moreover, oxygen may be located in the headspace of the bag after the bag is filled with wine and sealed during the packaging process, and oxygen can also escape from the wine itself over time and fill the headspace in the bag. Consequently, wine stored with sulfites in a sealed flexible bag still can spoil due to exposure to oxygen over time and, thus, has a limited shelf life.
More sulfites can be added to the wine during the packaging process to help prevent oxidation and extend the shelf life of the wine, but too many sulfites can negatively affect the taste of the wine. In addition, oxygen in the headspace of the bag can be replaced with an inert gas like nitrogen during the packaging process, but replacing oxygen in the headspace with an inert gas does not prevent the ingress of oxygen into the bag from the outside environment.